63 lines
1.8 KiB
Diff
63 lines
1.8 KiB
Diff
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From 15beb4b193b2714d88107e7dffca781798684e7e Mon Sep 17 00:00:00 2001
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From: Daiki Ueno <ueno@gnu.org>
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Date: Fri, 29 Jan 2021 14:06:05 +0100
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Subject: [PATCH 1/2] key_share: avoid use-after-free around realloc
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Signed-off-by: Daiki Ueno <ueno@gnu.org>
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---
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lib/ext/key_share.c | 12 +++++-------
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1 file changed, 5 insertions(+), 7 deletions(-)
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diff --git a/lib/ext/key_share.c b/lib/ext/key_share.c
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index ab8abf8fe..a8c4bb5cf 100644
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--- a/lib/ext/key_share.c
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+++ b/lib/ext/key_share.c
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@@ -664,14 +664,14 @@ key_share_send_params(gnutls_session_t session,
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{
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unsigned i;
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int ret;
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- unsigned char *lengthp;
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- unsigned int cur_length;
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unsigned int generated = 0;
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const gnutls_group_entry_st *group;
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const version_entry_st *ver;
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/* this extension is only being sent on client side */
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if (session->security_parameters.entity == GNUTLS_CLIENT) {
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+ unsigned int length_pos;
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+
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ver = _gnutls_version_max(session);
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if (unlikely(ver == NULL || ver->key_shares == 0))
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return 0;
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@@ -679,16 +679,13 @@ key_share_send_params(gnutls_session_t session,
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if (!have_creds_for_tls13(session))
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return 0;
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- /* write the total length later */
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- lengthp = &extdata->data[extdata->length];
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+ length_pos = extdata->length;
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ret =
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_gnutls_buffer_append_prefix(extdata, 16, 0);
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if (ret < 0)
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return gnutls_assert_val(ret);
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- cur_length = extdata->length;
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-
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if (session->internals.hsk_flags & HSK_HRR_RECEIVED) { /* we know the group */
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group = get_group(session);
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if (unlikely(group == NULL))
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@@ -736,7 +733,8 @@ key_share_send_params(gnutls_session_t session,
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}
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/* copy actual length */
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- _gnutls_write_uint16(extdata->length - cur_length, lengthp);
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+ _gnutls_write_uint16(extdata->length - length_pos - 2,
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+ &extdata->data[length_pos]);
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} else { /* server */
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ver = get_version(session);
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--
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2.30.2
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